The present invention is related to liquid crystal display (LCD) assemblies and the associated assembly process. Specifically, this invention addresses structural support for the LCD, back lighting for the LCD, and mounting of the LCD assembly to its housing or support. When the LCD assembly support is a printed circuit board, the invention provides a means for efficient manufacturing.
One traditional LCD assembly, as shown in FIG. 1, includes a lightpipe 20, a separate bezel 12 to secure the LCD 10 to the lightpipe 20, a light source 18, and a support structure 14. The lightpipe 20 provides a medium through which illumination is directed from a light source 18 towards the LCD 10 to provide back lighting, and the lightpipe 10 provides structural support for the LCD. Incandescent lamps or light emitting diodes are typical light sources for back lighting the LCD, and there is usually a requirement for uniform dispersion of the back light. The bezel 12 is used to secure the LCD 10 to the lightpipe 20, and tabs 22 located on the bezel 12 are used to mount the lightpipe 20 to a printed circuit board or other support structure 14. An elastomeric connector 24 or a heat seal connector (not shown) provides electrical connection to the LCD 10. The LCD assembly is controlled by display circuitry 16.
A LCD assembly design is not very valuable if it cannot be reliably manufactured. The twist tab operation associated with metal bezels is undesirable because of inherent problems with alignment, assembly time, and process reliability. Additionally, having a separate lightpipe and bezel necessitates some locational tolerance between the bezel and the lightpipe thus increasing the total height of the assembly.
Furthermore, the LCD assemblies described in the prior art do not lend themselves to automated manufacturing, or even simple hand assembly. Alignment problems can arise from positioning the LCD on the lightpipe to mounting the LCD assembly to its support. Where elastomeric connectors are used, controlling the compression range of the elastomeric connectors is essential. These and other related problems affect the quality, reliability, and manufacturability of LCD assemblies.